Effect of Electric Field Treatment on Vacancy of Inconel 718 Superalloy at 1073 K

2011 ◽  
Vol 409 ◽  
pp. 769-773 ◽  
Author(s):  
Yao Wang ◽  
Lei Wang ◽  
Xin Yu Zhang ◽  
Yan Long Li ◽  
Yang Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Positron Annihilation ◽  
Inconel 718 ◽  
Lattice Site ◽  
Vacancy Concentration ◽  
Three Dimensional ◽  
Positron Annihilation Lifetime ◽  
Normal Lattice ◽  
Inconel 718 Superalloy ◽  
Electric Field Treatment

Effect of electric field treatment with different intensities on vacancy of Inconel 718 aged at 1073 K was investigated. The positron annihilation lifetime (PAL) and corresponding concentration of vacancies were measured by positron annihilation technique. It was found that atomic vibration at lattice site can be promoted by an external electric field performed on Inconel 718 superalloy during aged at elevated temperature. Some atoms owing the higher vacancy formation energy or larger radius will jump out from the normal lattice sites and form defects, which is leading to the increase of PAL of monovacancy. Under continuous effect on electric field, monovacancies will transform to three-dimensional vacancies of lower energy and vacancy clusters. Moreover, the vacancy concentration of Inconel 718 superalloy can be improved evidently by electric field treatment, and the average PAL of vacancies can be up to 6.3% when the electric field intensity is up to 8 kV/cm, which is very useful for controlling the microstructures evolution and properties of the superalloy, such as solute redistribution and precipitations.

Metrology and Morphology of γ’ and γ’’ Nanoparticles in Inconel 718 Measured by FIB-SEM Tomography

2013 ◽  
Vol 197 ◽  
pp. 131-136 ◽  
Author(s):  
Krzysztof Kulawik ◽  
Beata Dubiel ◽  
Aleksandra Czyrska-Filemonowicz
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Quantitative Analysis ◽  
Inconel 718 ◽  
Three Dimensional ◽  
Precise Method ◽  
Inconel 718 Superalloy

Quantitative analysis of γ' and γ" phase nanoparticles in Inconel 718 was performed using FIB-SEM tomography. Three-dimensional visualisation showed that γ' particles are spherical, while γ" precipitates are disc-shaped. The dependence of the particle size of both phases on the heat treatment applied was detected. It was proven that the FIB-SEM tomography is a very precise method for metrology and morphology investigation of nanoparticles precipitated in Inconel 718 superalloy.

scholarly journals Effect of Pressure and Temperature on Densification in Electric Field-Assisted Sintering of Inconel 718 Superalloy

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2546
Author(s):  
Liyong Ma ◽  
Ziyong Zhang ◽  
Bao Meng ◽  
Min Wan
Keyword(s):  
Electric Field ◽  
Inconel 718 ◽  
Sintered Sample ◽  
Sintering Process ◽  
Plastic Yield ◽  
Average Porosity ◽  
Wide Range ◽  
Conventional Sintering ◽  
Inconel 718 Superalloy ◽  
Field Assisted Sintering

Electric field-assisted sintering has ubiquitous merits over conventional sintering technology for the fabrication of difficult-to-deform materials. To investigate the effect of sintering pressure and temperature on the densification of Inconel 718 superalloy, a numerical simulation model was established based on the Fleck-Kuhn-McMeeking (FKM) and Gurson-Tvergaard-Needleman (GTN) models, which covers a wide range of porosity. At a sintering pressure below 50 MPa or a sintering temperature below 950 °C, the average porosity of the sintered superalloy is over 0.17 with low densification. Under a pressure above 110 MPa and a temperature above 1250 °C, the sintered superalloy quickly completes densification and enters the plastic yield stage, making it difficult to control the sintering process. When the pressure is above 70 MPa while the temperature exceeds 1150 °C, the average porosity is 0.11, with little fall when the pressure or temperature rises. The experimental results indicated that the relative density of the sintered superalloy under 70 MPa and 1150 °C is 94.46%, and the proportion of the grain size below 10 μm is 73%. In addition, the yield strength of the sintered sample is 512 MPa, the compressive strength comes to 1260 MPa when the strain is over 0.8, and the microhardness is 395 Hv, demonstrating a better mechanical property than the conventional superalloy.

Study of Fe75Al25 Alloys by the Mössbauer Spectroscopy Positron Annihilation Lifetime Spectroscopy (PALS), XRD and SEM

2013 ◽  
Vol 203-204 ◽  
pp. 137-141 ◽  
Author(s):  
Aneta Hanc-Kuczkowska ◽  
Jerzy Kansy ◽  
Grzegorz Dercz ◽  
Lucjan Pająk ◽  
Józef Lelątko ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Positron Annihilation ◽  
Mossbauer Spectroscopy ◽  
Vacancy Concentration ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
X Ray Diffraction ◽  
Slow Cooling ◽  
Positron Annihilation Lifetime ◽  
Mößbauer Spectroscopy

The structure, point defect and ordering parameter of Fe25Al samples is examined with the Mössbauer spectroscopy Positron Annihilation Lifetime Spectroscopy XRD and SEM. The studies are carried out for samples in as-cast state and after heat treatments: annealing for 24 hours at 900°C (or 1050°C) and either slow cooling with furnace or quenching to oil. Among the research method used, Mössbauer spectroscopy for determination of hyperfine structure parameters was adopted. These parameters, sensitive to changes in spin and charge electron densities in the nearest neighbourhood of a Mössbauer isotope nucleus, caused by specific configurations of atoms, are directly connected with the degree of ordering of a compound. Spectral analysis has been carried out using an authors’ software developed based on a theoretical model relating the shape of a Mössbauer spectrum to the sample microstructure. It has been shown that Mössbauer spectroscopy enables quantitative evaluation of the degree of ordering of phases occurring in samples characterised by large graining, in the case of which it is not possible to determine the long-range order parameter by X-ray diffraction. The PALS method only one type of defects is detected. The positron lifetime in these defects (V) suggests that they are quenched-in Fe-monovacancies (VFe). The vacancy concentration strongly depends on the rate of cooling.

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

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